Imaging of the body serves multiple purposes, including any of i) assessing tissue structures and anatomy; ii) planning and/or guiding interventions on localized regions of the body; and iii) assessing the result of interventions that alter the structure, composition or other properties of the localized region. Ultrasound and optical imaging techniques can be very useful for a variety of minimally invasive applications, including intravascular and intracardiac procedures. By way of example, two particularly important implementations of minimally invasive ultrasound are intravascular ultrasound (IVUS), for imaging blood vessels, and intracardiac echocardiography (ICE) for imaging cardiac chambers. Both ICE and IVUS are minimally invasive, and involve placing one or more ultrasound transducers inside a blood vessel or cardiac chamber to take high quality images of these structures.
Optical imaging methods based on fiber optic technology used in the field of medicine include optical coherence tomography, angioscopy, near infrared spectroscopy, Raman spectroscopy and fluorescence spectroscopy.
Imaging probes can be configured using mechanically scanning mechanisms where the direction of the energy beams used to generate images is determined by the mechanical motion of one or more components responsible for the emission and/or sensing of imaging energy. Imaging probes can also be constructed using arrays of imaging elements, such as phased array ultrasound imaging probes and fiber optic bundles or charge coupled devices used in various optical imaging devices such as angioscopes, endoscopes and laryngoscopes.
Examples of 3D scanning mechanisms are provided in U.S. Pat. No. 8,214,010 (“Scanning mechanisms for imaging probe”, Courtney et al), the entirety of which is herein incorporated by reference.
Areas of application for 3D minimally invasive imaging include image guidance for procedures in structural heart disease and electrophysiology procedures. It is often necessary to place catheters within specific positions in the cardiac chambers in order to perform a therapeutic maneuver, such as the implantation of a device (such as a closure device for patent foramen ovales, valvular repair or replacement devices, left atrial appendage closure devices) or the placement of a therapeutic catheter (such as an ablation or cryotherapy catheter). It may also be necessary to guide intermediate steps in a procedure, such as crossing the atrial septum of the heart. The use of minimally invasive imaging can facilitate these steps. 3D intracardiac echo (3D ICE), is one such technology for this purpose.